1. Field of the Invention
The present invention relates to an improvement in a roller conveyer for conveying articles employed in industrial production lines, civil engineering or construction sites, and various other fields.
2. Description of the Related Art
Conventionally, chain-driven roller conveyers have been in wide use. Such a chain-driven roller conveyer includes rollers, sprockets fixedly attached to the roller shafts of the rollers, and a chain fitted around the sprockets. A single motor drives the chain so as to rotate the rollers, thereby conveying articles on the rollers. In some cases, the roller conveyer may assume the form of a free-flow conveyer. Specifically, the rollers can rotate about the corresponding shafts, while sliding relative thereto, so that articles being conveyed can be accumulated on the conveyer.
In this conventional chain-driven roller conveyer, elongation of the chain occurs with long-term use and the chain length must be adjusted. Also, running of the chain raises a noise problem. The chain-driven roller conveyer is generally intended to convey articles linearly on a horizontal plane. When the chain-driven roller conveyer is to have a vertically curved conveyance path surface (up-and-down conveyer), the structure thereof unavoidably becomes very complex. Also, the structural features of the chain-driven roller conveyer do not allow for a curved conveyer.
Recently, a shaft-driven roller conveyer has begun to replace a chain-driven roller conveyer. FIG. 20 shows a shaft-driven roller conveyer 01. As shown in FIG. 20, a shaft 040 extends in the direction of conveyance and is rotated by means of a motor 018. Bevel gears 041 are fixedly attached to the shaft 040 at positions corresponding to rollers 06 on one lateral side of the conveyance path. The bevel gears 041 convert rotation of the shaft 040 to rotation of corresponding roller shafts 042, which extend perpendicular to the shaft 040, thereby rotating the rollers 06 at opposing ends of the shafts 042 (lateral side of the conveyance path).
This shaft-driven roller conveyer does not require adjustment of chain length and features produces less noise as compared with a chain-driven roller conveyer. However, a mechanism for changing direction of rotation and including the bevel gears 041 has a relatively complex structure. Moreover, the width of the drive mechanism accounts for a relatively large percentage of the width of the conveyer, thus limiting the width of the conveyance path surface, i.e., thus being disadvantageous in terms of space efficiency. Also, since the shaft 040 is straight, the shaft-driven roller conveyer cannot have a horizontally or vertically curved conveyance path surface.
An object of the present invention is to solve the above-mentioned problems involved in the conventional roller conveyers and to provide a roller conveyer having a simple, compact power transmission mechanism, facilitating change in specifications, easily taking the form of a curved conveyer or an up-and-down conveyer, facilitating maintenance, and reducing cost of manufacture.
To achieve the above object, the present invention provides a roller conveyer adapted to convey articles on and along a conveyance path. The roller conveyer comprises a motor and a plurality of rollers which are disposed on at least at opposing lateral sides of the conveyance path and are adapted to convey articles on and along the conveyance path through rotation thereof. The rollers disposed on at least one lateral side of the conveyance path each comprise a roller body and a first gear attached coaxially to the roller body. The roller body and the first gear may rotate either together or with relative sliding rotation (slippage) therebetween. Adjacent first gears are interlockingly engaged to thereby rotate the rollers concurrently. Rotational torque of the motor is input directly or indirectly to any one of the first gears.
Through employment of the above-described conveyer configuration, the output shaft of the motor (the motor shaft or the output shaft of a speed reducer when the motor shaft or the motor is equipped therewith) and the shafts of the first gears can be disposed on the common conveyance path surface while being oriented in the same direction perpendicular to the direction of conveyance. Thus, the rotation transmission mechanism can be a simplified structure and compact, thereby reducing the cost of manufacture of the conveyer. Since the conveyer of the present invention does not use bevel gears, which are expensive, the cost of manufacture thereof can be further reduced even though the number of gears used is equal to that in a conventional counterpart. In contrast to a bevel gear system, the gears are engaged such that the shafts thereof are oriented in the same direction, thereby achieving a higher efficiency in transmission of torque.
All the first gears are interlockingly engaged while the motor is connected directly or indirectly to any one or more of the first gears, thereby causing all the rollers to effect a conveying operation. In order to increase conveyance power, a plurality of motors may be connected to a plurality of any first gears in the same manner. Thus, since the number of motors and the first gears to which the motors are connected is not particularly limited, the specifications of the roller conveyer can be flexibly modified.
A motor drive unit is not necessarily disposed at the upstream or downstream end of the conveyer, but may be disposed at an intermediate portion of the conveyance path. Thus, there is no need to reserve space for the motor drive unit or a tail unit in addition to space for the conveyance path, thereby economizing on space.
Furthermore, the conveyer of the present invention does not require adjustment of chain tension, which becomes necessary for the conventional chain-driven roller conveyer after long-term use thereof, thereby facilitating maintenance.
Preferably, the adjacent first gears are interlockingly engaged by means of a single or a plurality of second gears interposed therebetween. As a result, through modification of the diameter or number of the second gears, the roller pitch can be modified freely, thereby enabling further flexibility in modification of roller conveyer specifications. Since the output shaft of the motor, the shaft of the first gear, and the shaft of the second gear can be disposed on the common conveyance path surface while being oriented in the same direction, perpendicular to the direction of conveyance, the rotation transmission mechanism can be a simplified structure and compact, thereby reducing the cost of manufacture of the conveyer.
Preferably, at least either the first gears or the second gears each have a diameter which varies in the direction of an axis of rotation, so as to curve the conveyance path.
As a result, a curved conveyer can be manufactured easily. Through modification of the varying degree of gear diameter, the curvature of a curved conveyer can be modified easily, so that a curved conveyer having a desired curvature can be manufactured easily.
Preferably, a plurality of rollers are gradually and sequentially varied in height of rotation axis above a common horizontal plane along the direction of conveyance of the conveyance path so as to vertically curve the surface of the conveyance path. As a result, an up-and-down conveyer can be manufactured easily. Through modification of the degree of ascent or descent or through employment of various combinations of ascent and descent, the shape of the conveyance path surface can be freely designed.
Preferably, the motor is disposed at an intermediate portion of the conveyance path with respect to the direction of conveyance to minimize load accumulated in gears located in the vicinity of the motor decreases, thereby improving efficiency in transmission of conveyance power. Since the durability of gears is improved, the strength of gear material can be decreased accordingly, thereby reducing cost of manufacture of the conveyer.
Preferably, the roller conveyer is divided into a plurality of conveyer sections in the direction of conveyance along the conveyance path. Engagement of adjacent first gears is broken at a boundary between adjacent conveyer sections and at least one conveyer section equipped with a motor can change the direction of conveyance.
As a result, the various conveyer sections can assume different structure and operation. For example, the conveyer sections can be motor-driven or manually driven; a certain conveyer section may be stopped while other conveyer sections remain in operation; and one or more motor-driven conveyer sections can change the direction of conveyance. Thus, a single roller conveyer can provide for selection from among various forms of conveyance. In other words, a single roller conveyer can provide a plurality of different functions.
Preferably, another conveyer is disposed in the vicinity of the conveyer section capable of changing the direction of conveyance such that articles conveyed thereon can be transferred onto the conveyer section from a direction perpendicular to the direction of conveyance of the conveyer section. As a result, it becomes possible to provide a conveyer facility in which the direction of conveyance of each article can be changed between opposing directions of conveyance perpendicular to the initial conveyance path.
The present invention further provides a roller conveyer adapted to convey articles on and along a conveyance path. The roller conveyer comprising a motor and a plurality of rollers which are disposed along the conveyance path and are adapted to convey articles on and along the conveyance path through rotation thereof. The rollers each comprise a roller body having a length corresponding to the width of the conveyance path, and a first gear located on at least one side of the conveyance path and attached coaxially to the roller body. The roller body and the first gear rotate either together or with relative rotation therebetween. The adjacent first gears are interlockingly engaged to thereby rotate the rollers concurrently. Rotational torque of the motor is input directly or indirectly to any one or more of the first gears. The roller conveyer of this latter embodiment can convey articles of any size not greater than the width of the conveyance path and provides effects similar to those yielded by the previously-described embodiment.